SUNER POWER Waterproof 12W 12V Solar Battery Charger & Maintainer Pro, Built-in UltraSmart MPPT Charge Controller, 12 Volt Solar Panel Trickle Charging Kits for Car Automotive Boat Marine RV Trailer

OK, to close the loop on this, the solar charger is good but I was not able to make it work with the coax power-jack connector. Apparently the charger has "smart" functions that check that a battery load is connected before supplying current. And it wasn't happy being connected to the front panel power jack. So I compromised by disconnecting the battery quick-connect inside the side panel, and connecting the solar charger directly through that connector (aka SAE connector). I used an extra 10' extension cord and a reversing polarity SAE-to-SAE union, which came together in the same package. I brought the extension cord out through the pull-cord opening, so it was no trouble to close the side panel. charger: https://www.amazon.com/dp/B08K2T4RPH?ref=ppx_yo2ov_dt_b_fed_asin_title&th=1 extension cord with adapter: https://www.amazon.com/dp/B0F2M42V7V?ref=ppx_yo2ov_dt_b_fed_asin_title&th=1 I will see if I can attach some photos.